Solvatochromic characterization of the liquid phase in liquid—supercritical CO2 mixtures

摘要: The solvatochromic dye phenol blue (N,N-dimethylindoaniline) is used to characterize the solvent strength (polarity) of saturated liquid phase in a series solvent-carbon dioxide binary mixtures. Data were obtained at 35 and 55 C pressures up {approximately}70 bar. Five solvents investigated--acetone, cyclohexane, methanol, THF, toluene. polarity decreases significantly with increasing pressure due carbon content this equilibrium. For example, acetone {approximately}60 bar equivalent pure cyclohexane ambient pressure. local environment about richer polar component than bulk composition would indicate. degree enrichment reflects concentration effects low pressure, both high where mixtures are highly compressible. NRTL model Renon Prausnitz able predict these compositions reasonable accuracy except CO{sub 2}-rich conditions compressibility important.